Oil seal

ABSTRACT

According to the present invention, a variable compression ratio machine having main bearings mounted in an eccentric carrier or support includes an oil seal located primarily in a main bearing cap for minimizing leakage of pressurized main bearing oil. The seal is located generally in a first main bearing fastener socket or fastener access cutout in order to minimize structurally compromising the bearing cap, and a portion of the fastener socket preferably is used as an oil passageway as well as for wrench access to the fastener. The oil seal and oil circuit of the present invention enable the size of the eccentric support to be minimized while also providing highly effective oil sealing. In more detail, a significant advantage of the present invention is that highly effective oil sealing is attained without compromising the size or structural integrity of the bearing cap. A second significant advantage of the present invention is that it can be manufactured and assembled at low cost. The oil sealing system of the present invention is robust and highly reliable.

This application relates to Provisional Application No. 60/849,314having a filing date of Oct. 3, 2006.

BACKGROUND OF THE INVENTION

Variable compression ratio can significantly increase the fuelefficiency of reciprocating piston engines used in passenger cars andtrucks. The present invention relates to variable compression ratiomechanisms having a crankshaft mounted in eccentric supports, and morespecifically to the oil supply circuit used to deliver oil to the mainbearings of the crankshaft.

Kurt Imren Yapici shows a variable compression ratio engine in U.S. Pat.No. 6,588,384 issued on Jul. 8, 2003 and assigned to FEV GmbH ofGermany. An oil galley that circumnavigates an eccentric support can beseen in FIG. 7 of the patent. A crankshaft main bearing for the engineis located in the eccentric support. An engine similar in design wasshown in Issue 22 of the FEV publication Spectrum, dated February 2003.A similar oiling system is also shown in U.S. Pat. No. 6,247,430 issuedon Jun. 19, 2001 to Yapici and also assigned to FEV. FIG. 3 of thepatent shows an oil feed passageway 20 in the engine housing that feedsa shallow channel 17 in the eccentric disk segment 3.2. Oil then flowsthrough drilling 18 to the crankshaft main bearings 2. A stiff eccentriccarrier is necessary for providing reliable and robust main bearinglife. The oil flow passageway 18 weakens the bearing cap and compromisesstiffness. Oil leakage from the oil circuit is believed to be a problemdue to the large area through which oil can leak. However, any furtherenlargement of the oil flow passageway 18 to accommodate oil sealingmeans would further risk the structural integrity of the bearing cap.Alternatively, oil sealing means could be installed in the housingwithout compromising the structure of the bearing cap. Referring againto FIG. 7 of U.S. Pat. No. 6,588,384, the leaking oil is used tolubricate the outer bearing surface of the eccentric support, with agroove around the outer circumference of the eccentric support beingprovided for distribution of the oil around the bearing surface. Ingeneral variable compression ratio engines offer the potential forsignificantly improving automobile fuel economy. Oil leakage with thesevariable compression ratio engines will increase oil pump powerconsumption, and increase aerodynamic drag and windage on the crankshaftwebs and other cranktrain components. These losses have been acceptedconsidering the larger gains that can be realized with variablecompression ratio, and the secondary benefit of using the leakage oilfor lubricating the eccentric support's outer bearings.

Mendler (the current applicant) shows another variable compression ratioengine in U.S. Pat. No. 6,443,107 issued on Sep. 3, 2002. FIG. 11 showsan oiling system similar to the FEV system. Mendler shows anothervariable compression ratio engine in U.S. Pat. No. 6,637,348 issued onOct. 28, 2003. FIGS. 1 and 2 show a fully enclosed oil circuit having nooil loss upstream of the main bearings. The United States Department ofEnergy and Argonne National Laboratory paid for construction of aprototype engine similar to the design shown in U.S. Pat. No. 6,637,348.A report on the engine by Charles Mendler and Roland Gravel waspublished by SAE International circa Jun. 5, 2002. The engine has provento be highly robust, and is currently located at Oak Ridge NationalLaboratory where it continues to be used for research. While theenclosed sealing system is robust, the manufacturing and assembly costof the enclosed oiling system is a significant disadvantage of thesystem. The eccentric carrier is also relatively large and heavy.

Lawrence et al. show a variable compression ratio engine havingeccentric main bearing supports in US Patent Application PublicationNo.: US 2006/0112911 A1, having a publication date of Jun. 1, 2006. FIG.3 show an oil feed passageway 46 in the engine housing that feeds ashallow channel 48 in the eccentric disk segment 26 a. Oil then flowsthrough drilling 42 to the crankshaft main bearings 34. A report on theengine authored by Kevin Duffy was published by SAE International Sep.25, 2006 titled Update on Diesel HCCI Activities at Caterpillar. Theengine has been built and tested. While fuel economy is important, theprimary objective for the Caterpillar engine is reduction of airpollutants using the variable compression ratio to change and controlthe combustion process. New federal regulations require enginemanufacturers to reduce emissions of nitrous oxides NOx and particulatematter PM. The pictures of the engine in the report closely match FIG. 3of the patent. Channel 48 has an exceptionally long length, and it isexpected that a significant amount of oil will leak from the system.Another problem with the oil circuit shown in FIG. 3 is that it is notstreamline. The sharp bends in the oil flow circuit will require use ofa higher oil feed pressure, which will result both in increased oilleakage and need for a more power consuming oil pump.

Accordingly, objectives of the present invention are to provide an oilsupply circuit for variable compression ratio engines of the eccentricmain bearing support type, that provides minimal oil loss and lowmanufacture and assembly cost. Another objective is to provide astreamline oil flow circuit in order to minimize the oil pump powerrequirements. Another objective is to provide an oil supply circuit andeccentric support design that is compact and light in design, while alsoproviding rigid support and alignment of the crankshaft main bearings.

SUMMARY OF THE INVENTION

According to the present invention, a variable compression ratio machinehaving main bearings mounted in an eccentric carrier or support includesan oil seal located primarily in a main bearing cap for minimizingleakage of pressurized main bearing oil. The seal is located generallyin a first main bearing fastener socket or fastener access cutout inorder to minimize structurally compromising the bearing cap, and aportion of the fastener socket preferably is used as an oil passagewayas well as for wrench access to the fastener. The oil seal and oilcircuit of the present invention enable the size of the eccentricsupport to be minimized while also providing highly effective oilsealing. In more detail, a significant advantage of the presentinvention is that highly effective oil sealing is attained withoutcompromising the size or structural integrity of the bearing cap. Asecond significant advantage of the present invention is that it can bemanufactured and assembled at low cost. The oil sealing system of thepresent invention is robust and highly reliable.

In the preferred embodiment of the present invention the seal includes aboss that nests into the fastener socket, thereby providing a low costmeans for retaining or holding the seal in position.

Preferably the seal has a hole through the boss for permitting the oilto flow into the lower portion of the fastener socket. A short oilpassageway or eccentric oil feed line is then used to direct oil fromthe fastener socket to the main bearings. The eccentric oil feed line isrelatively short and results in an acceptably small reduction of bearingcap stiffness.

The oil flow circuit is streamline and permits the oil feed pressure tobe minimized. The low feed pressure and the effective sealing meansaccording to the present invention enables oil pump power to beminimized and engine efficiency maximized. The oil seal is highlyreliable and has a low manufacturing and assembly cost.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is intended to illustrate a variable compression ratio engine ormachine having an oil seal according to the present invention.

FIG. 2 is a partial cutaway view of a portion of FIG. 1.

FIG. 3 shows a detail view of the sealing element.

FIG. 4 shows a second view of the sealing element.

FIG. 5 is similar to FIG. 2, but shows an alternate location for theinternal oil flow passageway.

FIG. 6 is intended to illustrate a bearing cap having an alternatefastener cutout shape and an alternate seal shape.

FIG. 7 is intended to illustrate the present invention with the oilsealing element located in the housing.

FIG. 8 is intended to illustrate the present invention in an eccentricsupport having a vertical bearing cap.

FIG. 9 is intended to illustrate a sealing element with an oil bleedgroove.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIGS. 1 and 2 are partial section views that are intended toschematically illustrate the preferred embodiment of the presentinvention. FIGS. 1 and 2 show an oil circuit for a variable compressionratio mechanism 1 having an oil supply 2, a housing 4 and at least onecylinder 6 mounted in the housing, a piston 8 mounted for reciprocatingmovement in the cylinder, a crankshaft 10 defining an axis about whichthe crankshaft rotates 12, and a connecting rod 14 connecting the pistonto the crankshaft. The variable compression ratio mechanism further hasat least one eccentric support 16 for supporting the crankshaft aboutthe rotational axis of the crankshaft 12. The eccentric support ismounted in the housing for pivoting relative to the housing about apivot axis 18. The pivot axis is substantially parallel to and spacedfrom the rotational axis of the crankshaft. Main bearings 20 are mountedin the eccentric support for supporting the crankshaft. The variablecompression ratio mechanism may be used in an engine or in otherapplications where a variable compression ratio is useful. The variablecompression ratio mechanism has a range of compression ratio settings,the range including at least a maximum compression ratio setting and aminimum compression ratio setting.

The eccentric support includes a bearing cap 22 and a plurality offasteners 24 for retaining the crankshaft in the eccentric support.

According to the present invention, the eccentric support furtherincludes a first fastener access cutout 26. According to the preferredembodiment of the present invention, eccentric support 16 also includesan oil seal 28 located primarily in the region of the first accesscutout 26.

Bearing cap 22 further including a bearing socket 30 for retaining oneor more of the main bearings 20 in eccentric support 16.

Housing 4 includes at least one housing oil feed line 32. Housing oilfeed line 32 has an upstream end 34, the upstream end being in fluidcommunication with oil supply 2, and a down stream end 36, the downstream end being in fluid communication with first fastener accesscutout 26.

Referring now to FIGS. 1, 2 and 3, eccentric support 16 includes aneccentric oil feed line 38. Eccentric oil feed line 38 has an upstreamend 40, the upstream end being connected to the first fastener accesscutout 26, and a down stream end 42, the down stream end being in fluidcommunication with main bearings 20.

Arrow 44, including upper and lower arrow segments, is intended toillustrate the primary oil flow pathway of the bearing oil. Primary oilflow pathway 44 extends from oil supply 2 to main bearings 20. Primaryoil flow pathway 44 including a first pathway section 45 extending fromoil supply 2 to first fastener access cutout 26, and a second pathwaysection 47 extending from first fastener access cutout 26 to mainbearings 20. According to the preferred embodiment of the presentinvention, the oil primarily flows directly out of the first pathwaysection 45 into the second pathway section 47, with the junction of thetwo pathways being located within the first fastener access cutout.

Eccentric support 16 has an outer bearing surface 46 having an outercircumference 48 for pivotably supporting eccentric support 16 inhousing 4. A small clearance gap 49 separates bearing surface 46 fromhousing 4.

According to the present invention, the oil circuit further has asealing curtain area 43 around first fastener access cutout 26. Thepreferred embodiment of the present invention includes sealing means forproviding a small sealing curtain area 43 through which oil can leakfrom the oil flow pathway 44. In more detail, the present inventionincludes sealing means for minimizing oil leakage between the housingoil feed line 32 and eccentric oil feed line 38. The sealing curtainarea 43 is generally the product of the average or approximate radialclearance gap 49 between the eccentric outer bearing surface includingthe sealing means and the housing 4 around curtain 43, and the minimumperimeter length around oil flow pathway 44 at the interface of theouter bearing surface 46 and housing 4. In more detail sealing curtainarea 43 is generally the smallest imaginary surface that if it wasimpermeable, would seal the clearance gap between the housing oil feedline 32 and the eccentric oil feed line 38 and stop oil leakage. In thepreferred embodiment of the present invention, oil seal 28 forms a sealwith housing 4 for minimizing the oil sealing curtain area 43, andthereby minimizing oil leakage. With respect to location of oil seal 28,the sealing function is preferably primarily located in or generally inthe first fastener access cutout in order to minimize the length of thesealed perimeter and in turn minimize curtain area. Preferably oil seal28 is located in first fastener access cutout 26, although the sealingmeans may extend outside of first fastener cutout 26 in some embodimentsof the present invention.

According to the present invention, oil supply 2 is in fluidcommunication with first fastener access cutout 26 through housing oilfeed line 32, and first fastener access cutout 26 is in fluidcommunication with main bearings 20 through eccentric oil feed line 38,thereby providing an oil supply circuit for delivering oil from oilsupply 2 to the main bearings 20 with minimal oil leakage.

Preferably, according to the present invention, the downstream end ofthe housing oil feed line 36 is directly or almost directly aligned withfirst fastener access cutout 26 at all compression ratio settings, toprovide streamlined flow of oil from the first pathway section 45 intothe second pathway section 47, for reducing the required oil pressure ofthe lubrication system.

Bearing cap 22 has a first fastener 50, and first fastener 50 has afirst fastener line of action 52. First fastener 50 has a first fastenerhead 54 having an approximate first fastener head circumference 56.Those skilled in the art will appreciate that various types of fastenerheads may be used according to the present invention. First fastenerhead circumference 56 and line of action 52 define an imaginary cylinder58. According to the preferred embodiment of the present invention,first fastener access cutout 26 includes at least the region insideimaginary cylinder 58 and inside outer circumference 48 that can beoccupied with oil that is freely in fluid communication with mainbearings 20. In embodiments of the present invention including a sealsuch as oil seal 28, first fastener access cutout 26 also refers to theregion inside seal 28. In the preferred embodiment of the presentinvention, first fastener access cutout 26 extends slightly outside 27of imaginary cylinder 58. According to the preferred embodiment of thepresent invention, the oil circuit passes through first fastener accesscutout 26, and in more detail eccentric oil feed line 38 and secondpathway 47 do not bypass first fastener access cutout 26.

Referring now to FIGS. 2 and 5, preferably according to the presentinvention the fastener access cutout 26 includes retaining means forretaining the oil seal in location. Eccentric support 16 may optionallyinclude a first fastener socket 60 or 60B. Optionally the access cutoutmay be the first fastener socket. FIG. 7 shows a first fastener accesscutout that is simply the first fastener socket. Preferably firstfastener socket 60 is slightly larger in diameter than imaginarycylinder 58 to provide access for assembly and wrench access. Firstfastener 50 may be a hex head bolt, a 12 point bolt (shown), a sockethead bolt, or another functional type of fastener. In the preferredembodiment of the present invention, oil seal 28 or 28B further includesa boss 62 or 62B. Preferably boss 62 or 62B is positioned in firstfastener socket 60 or 60B for retaining oil seal 28 or 28B in positionfor oil sealing.

Referring now to FIG. 2, preferably eccentric oil feed line 38 isconnected to first fastener socket 60 downstream of said first fasteneraccess cutout 26.

Oil seal 28 is intended to substantively minimizing leakage of oilbetween housing oil feed line 32 and eccentric oil feed line 38. Thoseskilled in the art will appreciate that various types and shapes ofsealing means can be used according to the present invention. FIGS. 1through 4 show oil seal 28. Referring now to FIG. 5, eccentric oil feedline 38B bypasses first fastener socket 60B. Oil seal 28B is similar tooil seal 28, but accommodates eccentric oil feed line 38B. Referring nowto FIG. 6, oil seal 28C has an alternate shape. Referring now to FIG. 7,an optional housing oil seal 29 is located in housing 4. Sealing meansmay be provided in some embodiments of the present invention byminimizing perimeter length around oil flow pathway 44 at the interfaceof the outer bearing surface 46 and housing 4, and by employing smallassembly tolerances to minimizing the radial clearance gap between theeccentric outer bearing surface 46 and the housing 4 and thereby providean acceptably small sealing curtain area. Preferably a removable oilseal is used such as oil seal 28, however, some embodiments of thepresent invention may be practiced without a removable sealing element,and in more detail where the sealing means includes small mechanicaltolerances to provide a small radial clearance gap, and a shortperimeter length to provide a small oil sealing curtain area.

Referring now to FIGS. 2-4, preferably the upstream end of saideccentric oil feed line 38 is in fluid communication with first fastenersocket 60, and boss 62 has a cutaway section or hole 64 to permit flowof oil from the housing oil feed line 32 to the eccentric oil feed line38. The upstream end of housing oil feed line 34 is in fluidcommunication with oil supply 2, and the down stream end of housing oilfeed line 36 is in fluid communication with first fastener socket 60.The upstream end of eccentric oil feed line 38 is in fluid communicationwith first fastener socket 60, and the down stream end of eccentric oilfeed line 42 is in fluid communication with main bearings 20.Accordingly, oil supply 2 is in fluid communication with first fastenersocket 60 through housing oil feed line 32, and first fastener socket 60is in fluid communication with main bearings 20 through eccentric oilfeed line 38, thereby providing an oil supply circuit for delivering oilfrom the oil supply 2 to the main bearings 20.

In the embodiment of the present invention shown in FIG. 2, the primaryoil flow pathway 44 from oil supply 2 to main bearings 20 is open at allof said compression ratio settings. In more detail, primary oil flowpathway 44 including a first pathway section 45 from oil supply 2 toimaginary cylinder 58 into first fastener socket 60 and a second pathwaysection from first fastener socket 60 through eccentric oil feed line 38to main bearings 20 that is streamline and open at all compression ratiosettings, thereby providing a streamline flow passageway with minimalpressure loss.

Referring now to FIGS. 1 and 2, variable compression ratio mechanism 1has a plurality of compression ratio settings including a firstcompression ratio setting 66. Flow pathway 44 also includes a first flowsegment 68 at first compression ratio setting 66. According to anembodiment of the present invention, first flow stream segment 68 andfirst fastener line of action 52 are generally aligned at firstcompression ratio setting 66, thereby providing a streamlined flow path.Preferably first flow segment 68 passes through oil seal 28.

FIG. 5 shows a blocked first fastener socket 60B. In the embodiment ofthe present invention illustrated in FIG. 5, first fastener socket 60Bis not considered part of first fastener access cutout 26 because oilcannot flow freely to main bearings 20 through first fastener socket60B. According to the present invention, the upstream end of eccentricoil feed line 38B may optionally bypasses first fastener socket 60B. Asmentioned previously, in the preferred embodiment of the presentinvention, first fastener access cutout 26 extends slightly outside 27of imaginary cylinder 58, as depicted in FIGS. 2 and 5. According to thepreferred embodiment of the present invention, the oil circuit passesthrough first fastener access cutout 26, and in more detail eccentricoil feed line 38 or 38B does not bypass first fastener access cutout 26.As shown in FIG. 5, eccentric oil feed line 38B may optionally bypassfirst fastener socket 60B, while being in fluid communication with firstfastener cutout 26 according to the present invention.

Referring now to FIGS. 1 through 4, preferably, according to the presentinvention oil seal 28 is made out of an elastic or compressive materialto provide sealing contact between the oil seal and housing 4. Oil seal28 may be formed out of PTFE or another functional material. Oil seal 28may additionally be made out of a composition of materials, such as ametal backed seal having a PTFE sliding surface.

Referring now to FIG. 5, a spring 70 may be used to bias oil seal 28Binto contact with housing 4 for providing a sealing contact. If used,preferably spring 70 is located in first fastener socket 60B.

Referring now to FIGS. 1, 2, 5 and 6, preferably first fastener accesscutout 26 is located in bearing cap 22. Referring now to FIG. 8,optionally first fastener access cutout 26D is located in the primarysupport structure 76 of the eccentric support 16B.

Referring now to FIGS. 2 and 9, eccentric support 16 has one or moreeccentric support outer bearings 46 that ride on a suitably formedmating surface in housing 4. Referring now to FIG. 9, oil seal 28E mayinclude bleed holes or grooves 74 for release of oil from the oil supplycircuit for lubricating the eccentric support outer bearings 46.

Referring again to FIG. 1, bearing cap 22 has a parting surface 78 and anormal imaginary plane 80. The normal imaginary plane is normal toparting surface 78, and the rotational axis of the crankshaft 12 liesentirely within imaginary plane 80. Bearing cap 22 has a minor half 82located on one side of said normal imaginary plane, and a major half 84located on the other side of said normal imaginary plane, where themajor half of the bearing cap is generally larger than the minor half ofthe bearing cap. Preferably, according to the present invention, firstfastener access cutout 26 is located in the major half 84 of bearing cap22, for providing a small diameter eccentric 16 having a first fasteneraccess cutout 26 long enough for an open oil circuit at all compressionratio settings.

Preferably according to the present invention, connecting rod 14advances from the region adjacent to minor half 82 of bearing cap 22 tothe region adjacent to major half 84 of said bearing cap 22, therebyproviding a crankshaft rotational direction yielding an eccentricsupport that is stiff and compact while also having a first fasteneraccess cutout and an eccentric oil feed line drilled hole that canweaken the part due to removed metal. According to the preferredembodiment of the present invention, the downstream end 42 of flowpathway 47 introduces oil to the crankshaft main bearings 20 slightlyafter piston 8 reaches its highest location in cylinder 6, therebyproviding optimum lubrication of main bearings 20 and crankshaft 10.

1. An oil circuit for a variable compression ratio mechanism having arange of compression ratio settings, and having an oil supply, a housingand at least one cylinder mounted in the housing, a piston mounted forreciprocating movement in the cylinder, a crankshaft defining an axisabout which the crankshaft rotates, and a connecting rod connecting thepiston to the crankshaft, said variable compression ratio mechanismfurther having at least one eccentric support for supporting thecrankshaft about the rotational axis of the crankshaft, the eccentricsupport being mounted in the housing for pivoting relative to thehousing about a pivot axis, the pivot axis being substantially parallelto and spaced from the rotational axis of the crankshaft, and mainbearings mounted in the eccentric support for supporting the crankshaft,said eccentric support further including a bearing cap and a pluralityof fasteners for retaining the crankshaft in the eccentric support, saidbearing cap further including a bearing socket for retaining one or moreof said main bearings in the eccentric support, said eccentric supportfurther having a first fastener access cutout, a housing oil feed linein said housing, said housing oil feed line having an upstream end, saidupstream end being in fluid communication with the oil supply, and adown stream end, said down stream end being in fluid communication withsaid first fastener access cutout, wherein said oil circuit further hasan eccentric oil feed line in said eccentric support, said eccentric oilfeed line having an upstream end, said upstream end being connected tosaid first fastener access cutout, and a down stream end, said downstream end being in fluid communication with said main bearings, whereinsaid oil supply is in fluid communication with said first fasteneraccess cutout through said housing oil feed line, and said firstfastener access cutout is in fluid communication with said main bearingsthrough said eccentric oil feed line, wherein said oil circuit furtherhas a sealing curtain area around said first fastener access cutout, andsealing means for providing a small curtain area for providing minimaloil leakage between said housing oil feed line and said eccentric oilfeed line, thereby providing an oil supply circuit for delivering oilfrom the oil supply to the main bearings with minimal oil leakage. 2.The oil circuit of claim 1 further including an oil seal forsubstantively minimizing leakage of oil between the housing oil feedline and the eccentric oil feed line, said seal being mounted on saideccentric support.
 3. The oil circuit of claim 1 further including anoil seal for substantively minimizing leakage of oil between the housingoil feed line and the eccentric oil feed line, said seal being locatedgenerally in said first fastener access cutout.
 4. The oil circuit ofclaim 3, wherein said first fastener access cutout includes retainingmeans for retaining said oil seal in location.
 5. The oil circuit ofclaim 3, further having a first fastener socket, and said oil sealfurther includes a boss, said boss being positioned in said firstfastener socket for retaining said oil seal in position for oil sealing.6. The oil circuit of claim 5, wherein the upstream end of saideccentric oil feed line is in fluid communication with said firstfastener socket, and said boss has a cutaway section to permit flow ofoil from the housing oil feed line to the eccentric oil feed line, saidupstream end of said housing oil feed line being in fluid communicationwith the oil supply, and said down stream end of said housing oil feedline being in fluid communication with said first fastener socket, saidupstream end of said eccentric oil feed line being in fluidcommunication with said first fastener socket, and said down stream endof said eccentric oil feed line being in fluid communication with saidmain bearings, wherein said oil supply is in fluid communication withsaid first fastener socket through said housing oil feed line, and saidfirst fastener socket is in fluid communication with said main bearingsthrough said eccentric oil feed line, thereby providing an oil supplycircuit for delivering oil from the oil supply to the main bearings. 7.The oil circuit of claim 1, further having a first fastener socket,wherein said oil circuit has a primary oil flow pathway from said oilsupply to said main bearings at all of said compression ratio settings,said primary oil flow pathway including a first pathway section fromsaid oil supply to said first fastener socket and a second pathwaysection from said fastener socket to said main bearings, therebyproviding a streamline flow passageway with minimal pressure loss. 8.The oil circuit of claim 5, wherein the upstream end of said eccentricoil feed line bypasses said first fastener socket.
 9. The oil circuit ofclaim 2 wherein said oil seal is made out of a compressive material forprovide seating contact between said oil seal and said housing.
 10. Theoil circuit of claim 2 further including a spring for providing sealingcontact between said oil seal and said housing.
 11. The oil circuit ofclaim 10 wherein said spring is located in said first fastener socketfor providing sealing contact between said oil seat and said housing.12. The oil circuit of claim 1, where in said first fastener accesscutout is located in said bearing cap.
 13. The oil circuit of claim 1,further including eccentric support outer bearings, and bleed holes forrelease of oil from the oil supply circuit for lubricating the eccentricsupport outer bearings.
 14. The oil circuit of claim 12, wherein saidbearing cap has a parting surface and a normal imaginary plane, saidnormal imaginary plane being normal to said parting surface, therotational axis of the crankshaft being entirely within said imaginaryplane, said bearing cap having a minor half located on one side of saidnormal imaginary plane, and a major half located on the other side ofsaid normal imaginary plane, said major half of said bearing cap beinggenerally larger than said minor half of said bearing cap, wherein saidfirst fastener access cutout is located in said major half of saidbearing cap, for providing both a small eccentric support and a firstfastener access cutout long enough for an open oil circuit at allcompression ratio settings.
 15. The oil circuit of claim 14, whereinsaid connecting rod advances from the region adjacent to said minor halfof said bearing cap to the region adjacent to said major half of saidbearing cap, thereby providing a crankshaft rotational directionyielding an eccentric support that is stiff and compact while alsohaving a first fastener access cutout and an eccentric oil feed linedrilled hole.
 16. The oil circuit of claim 1 wherein said sealing meansincludes a small curtain area circumference and a small assemblytolerance between said housing and said outer bearing surface.
 17. Theoil circuit of claim 1, further having a first compression ratiosetting, a first fastener line of action and a first flow streamsegment, said flow stream segment being generally aligned with saidfirst fastener line of action at said first compression ratio setting.18. The oil circuit of claim 17, further including an oil seal forsubstantively minimizing leakage of oil between the housing oil feedline and the eccentric oil feed line, wherein said first flow streamsegment passes through said oil seal.
 19. The oil circuit of claim 1,further having a first fastener socket, wherein said eccentric oil feedline is connected to said first fastener socket downstream of said firstfastener access cutout.